Midtrimester abortion with urea, prostaglandin F2alpha, laminaria, and oxytocin. A new regimen

Abstract

This study was undertaken to determine a method of amino infusion that would 1) produce abortion within 12 hours; 2) be relatively free from risks of coagulapathy and electrolyte imbalance; 3) not result in delivery of liveborns; and 4) incur minimal gastrointestinal side effects from prostaglandin. Patients were randomly assigned to 1 of 3 groups unless history and examination revealed a contraindication to the use of prostaglandin. Three infusions were used: prostaglandin alone, urea alone, and a combination of urea and prostaglandin. All patients had pre-infusion laminaria inserted and all received oxytocin following infusion. There was a significant difference in instillation to abortion time when comparing the three groups and a marked reduction in gastrointestinal side effects using a lower dosage of prostaglandin. The synergistic effect of urea and prostaglandin F2alpha, previously demonstrated was further enhanced by the use of oxytocin and laminaria. This produced a mean instillation to abortion time significantly shorter than previous studies have shown and, indeed, offers a means of second trimester abortion suitable for use in ambulatory surgery facilities, precluding the high cost of inpatient care.

PIP: The purpose of this study was to determine a method of amnioinfusion which would 1) keep the instillation to abortion time (IAT) within 12 hours; 2) eliminate, as far as possible, the risk of coagulaopathy and electrolyte imbalance; 3) avoid delivery of liveborn fetuses; 4) reduce gastrointestinal side effects from prostaglandin. 89 midtrimester abortion applicants, divided into 3 groups, had laminaria inserted the afternoon prior to admission. 3 types of infusion were given: 40 mg PGF2 alpha, urea, and a combination of urea solution and 20 mg PGF2 alpha. Upon completion of the infusion the laminaria was removed. 1 hour later oxytocin was administered to all patients; the purpose of the delay was to allow time for prostaglandin impact. 21.4% of cases given urea, 47.8 of those given PGF2 alpha, and 77% of those given urea and PGF2 alpha had aborted 12 hours after infusion. 63.7% of those receiving the combination had aborted 9 hours after infusion. Gastrointestinal side effects were observed in 35% of cases given the higher prostaglandin dosage, compared to only 10% of cases given the lower dosage. The findings indicate that the synergistic effect of urea and prostaglandin was enhanced by the concurrent use of laminaria and oxytocin; the urea dosage was only half of that used in previous studies of synergism, the prostaglandin dosage half of that of prostaglandin only infusions. It seems clear that the initial prostaglandin impact is reinforced by simultaneous administration of urea. Future tests will determine whether the rate of progesterone withdrawal is increased by the synergistic activity of urea and PGF2 alpha in combination.